A variety of molded plastic truck bed liners have been known and available in the automotive industry for quite some time, as exemplified in U.S. Pat. Nos. 3,814,473 (issued to Lorenzen on Jun. 4, 1974); 3,881,768 (issued to Nix on May 6, 1975); and 4,181,349 (issued to Nix et al. on Jan. 1, 1980). Along with truck bed liners of varying design and application, there have also been provided a variety of fastening structures to insure that the liners are retained within the truck bed during use. For example, the Nix et al. '349 patent mentioned above discusses various types of fastening means which may be employed to secure the liner to the truck bed, and, particularly, illustrates a preferred toggle bolt fastener which can be inserted through pre-existing holes in the top flange of the truck bed sidewalls.
Other examples of fastening arrangements for truck bed liners are shown in U.S. Pat. Nos. 4,740,026 (which issued to Wagner on Apr. 26, 1988), 4,595,229 (which issued to Wagner on Jun. 17, 1986), 4,796,942 (which issued to Robinson, et al. on Jan. 10, 1989), 4,659,133 (which issued to Gower on Apr. 21, 1987), and 4,768,822 (which issued Gower on Sept. 6, 1988). These patents each disclose and illustrate various attachment structures which extend through portions of the liner walls for selective interaction with the downturned inner portion of the truck bed sidewall. The Gower '133 patent also shows a J-shaped retaining device which includes adhesive material, and which is designed to slip over the upper edge of the liner sidewall and to be adhesively adhered for engagement with the truck bed ledge wall. Each of these devices, however, further requires manipulation of bolts or screws for tightening the devices in place, or the requirement for the removal of adhesive coverings and careful placement of J-shaped hooks.
An improved snap-lock fastener for truck bed liners is shown in U.S. Pat. No. 5,046,775 (which issued to Howard Marcum et al. on Sep. 10, 1991). This fastening device conveniently snaps into a preformed aperture in the liner sidewall to mechanically interact with the rail structure of the truck bed to secure the liner in place without requiring drilling or complex attachment devices. This snap lock fastener is also easily adaptable to a variety of installation applications, and mounts substantially flush with the walls of the truck bed liner so as not to interfere with the full use of the liner.
Additionally, a number of new pickup truck bed designs include additional inner panel structures which make the inwardly extending flange or rail structure required for the presently available "drilless" anchoring means (and some of the snap-type fastening systems) inaccessible. Similarly, many new truck bed designs also eliminate the stake pockets commonly found along the top edges of the truck bed side walls, and which were sometimes used to accommodate toggles or other bed liner fastening devices. Some of the newer truck styles have eliminated the inwardly extending wheel wells and provide sidewalls which are substantially vertical from bottom to top. A number of these designs also include an inwardly extending tie-down bar near the rear portions of each sidewall to facilitate the attachment of tie-down ropes and the like. Because the previous fastening systems requiring some kind of truck bed rail or flange are not applicable or adaptable to many of the new truck bed designs, a new liner and fastening system was needed.